Abstract: The electrical discharge machining device includes storage apparatus for storing the two-dimensional contour pass of the machined shape formed by the primary machining operation, the dimension of the taper of the side surface of the workpiece to be machined, the amounts of feed of the electrode in a given Z direction with respect to the movements of the electrode in the X and Y direction under respective machining conditions; information adding apparatus for adding offset information to the above-mentioned contour pass; machining operation number calculating apparatus, in accordance with a previously obtained machining depth per round about an electrode pass, for calculating the number of machining operations to be repeatedly executed around the electrode pass until a target depth is obtained; offset displacement amount calculating apparatus for calculating an offset displacement amount per round about the electrode pass in accordance with the length in the above-mentioned side surface direction of the side s

Abstract: A wire-cut electric discharge machining apparatus and a control method for the wire-cut EDM apparatus. The amount of current pulses supplied to a machining gap can be measured precisely without a detection delay to thereby detect the occurrence of faulty machining such as wire electrode breakage and centralized arcs.

Abstract: An electric discharge machine includes a pulse determining section, which determines whether an electric discharge pulse is an effective electric discharge pulse contributing to machining or an ineffective pulse not contributing to machining, a pulse counting section, which counts the number of electric discharge pulses determined to be effective electric discharge pulses, a machining speed measuring section, which measures the machining rate in the axial direction, a dividing section, which divides the total number of electric discharge pulses by the machining rate in the axial direction, a storage section, which stores predetermined constant data corresponding to electric conditions such as a waveform for a current due to materials of an electrode and a workpiece or generation of electric discharge, and a machined area computing section, which computes a machined area according to the divided data and the stored constant data. A method for controlling the electric discharge machine is also described.

Abstract: An apparatus and process for forming surface layers on electrodes by electron discharge machining. A machining gap, between an electrode and a workpiece is filled with a dielectric mixture containing metallic or submetallic powder. The apparatus uses a swinging mechanism to move the electrode during processing. The apparatus uses a high-voltage superposition circuit to superpose a voltage of 100-400 V across the gap. The apparatus uses a current limiting resistor of 100-300 .OMEGA. to ensure that the main circuit supplies a low voltage of approximately 100 V to the machining gap. In a second embodiment, the apparatus prevents electrode cracking by dispersing the discharges throughout, and widening, the machining gap.

Abstract: An apparatus and process for forming surface layers on electrodes by electric discharge machining. A machining gap, between an electrode and a workpiece is filled with a dielectric mixture containing metallic or submetallic powder. The apparatus uses a swinging mechanism to move the electrode during processing. The apparatus uses a high-voltage superposition circuit to superpose a voltage of 100-400 V across the gap. The apparatus uses a current limiting resistor of 100-300.OMEGA. to ensure that the main circuit supplies a low voltage of approximately 100 V to the machining gap. In a second embodiment, the apparatus prevents electrode cracking by dispersing the discharges throughout, and widening, the machining gap.

Abstract: A surface treatment method and apparatus therefor for providing wear and corrosion resistance, which includes relatively rotating a modified metallic member to be surface modified and a block, which may be metal only or may include a modifying material (e.g., ceramic or W-C/Co), and generating electrical discharge between the block and the modified metallic member to form a modification layer on the surface of said modified metallic member. If the modifying material is not in the block, it can be supplied via a dielectric bath or spray at the discharge interface. In this manner, the cutting edges of a cutting tool with a complicated shape can be surface modified easily to carry out tool surface treatment which increases a cutting tool life greatly. Cutting and surface treatment can be performed alternately as determined by a controller.

Abstract: An electric discharge machine having a source of pulse power, optionally including bipolar pulses, which is connected to an electrode which forms a gap with a workpiece and is operative to provide both machining and finishing processes. Switching of power to the machining gap and impedance matching at the machining gap, in order to suppress the influence of the capacitance of the high-speed machining feeder cables connected to the machining gap in finishing, is provided so that machining can be performed at high accuracy with a properly timed and shaped discharge current. Impedance matching is provided by selectively switching among plural capacitances or inductances, which may be in the form of cables or printed patterns on a circuit board which have predetermined values, such as a geometric series values of which coefficient is 2.

Abstract: An electrical discharge machine for machining a workpiece with the application of a voltage to a machining gap formed between an electrode and the workpiece which has a direct-current power supply for supplying a machining current and a current limiting device connected in series with the direct-current power supply for limiting the machining current. A switching device is connected in series with the direct-current power supply and current limiting device and is operative to provide a voltage to the machining gap and to form a direct-current pulse. A series circuit of an inductance and a capacitor is provided in parallel with the machining gap.

Abstract: An apparatus for forming surface layers on electrodes by electric discharge machining. A machining gap, between an electrode and a workpiece is filled with a dielectric mixture containing metallic or submetallic powder. The apparatus uses a swinging mechanism to move the electrode during processing. The apparatus uses a high-voltage superposition circuit to superpose a voltage of 100-400 V across the gap. The apparatus uses a current limiting resistor of 100-300.OMEGA. to ensure that the main circuit supplies a low voltage of approximately 100 V to the machining gap. In a second embodiment, the apparatus prevents electrode cracking by dispersing the discharges throughout, and widening, the machining gap.

Abstract: An electric discharge machining apparatus of the travelling wire or sink type includes at least one secondary electrode which is immersed in the dielectric at least during machining. A microvoltage power supply is used to create a micropotential difference between the workpiece and the secondary electrode so that the workpiece becomes a negative pole. Maintaining this arrangement both during machining and non-machining times prevents the workpiece from being subjected to positive-pole oxidation.

Abstract: A wire cut electrical discharge machining apparatus or machining a corner in a workpiece, which uses a gap error voltage to generate a command velocity component. A velocity control device is used for clamping a command velocity at not more than a set velocity value. Alternatively, the error voltage is used to generate the combination of an integration component and a transient response component which is used to generate a command velocity. Also, an inside corner with a small minimum corner radius can be machined at high accuracy by defining a plurality machining tracks, which include a circular portion at an inside corner, to have the same radius.

Abstract: An electrical discharge machine equipped with a machining gap voltage application circuit having switching circuits capable of switching between a first voltage application state wherein one terminal of a first direct-current power supply is connected to an electrode and the other terminal thereof is connected to a workpiece and a first voltage is applied to the gap, a second voltage application state wherein the one terminal is connected to the workpiece and the other terminal is connected to the electrode and a second voltage is applied to the gap, and a second voltage application reset state where the second voltage is not applied to the gap. The switching circuits are operative during a first period of time when the second voltage application state and a second voltage application reset state alternate with each other, and a second period of time when the first voltage application state exists, the first and second periods are repeated in a predetermined sequence.

Abstract: In an electric discharge machining apparatus, a workpiece electrically connected to a body of the machine and a jig on which the workpiece rests are electrically isolated from each other. The body and the workpiece are selectively switched in open-circuit/short-circuit by a switch. Switching can be made on the stool or the workpiece. Further, the switch and the workpiece and the jig are connected to each other by a coaxial cable.

Abstract: A device for positioning a first and second conductive elements and, in particular, detecting contact at a gap therebetween without causing damage to either element. A pulse voltage, having a low duty, is applied to the gap. The occurrence of a contact is identified by a voltage drop at the gap, which is detected by comparing the gap voltage to a reference. A control circuit, comprising a flip-flop or one-shot operative in synchronism with the source of pulse voltage, generates a contact identification signal in response to the detection of a voltage drop at the gap.

Abstract: An electric discharge machine having a machining solution tank for storing a machining solution containing machining particles, a machining vessel filled with the machining solution to machine a workpiece, and a machining solution circulating system for circulating the machining solution between the machining solution tank and the machining vessel. The vessel has a pair of machining solution jetting devices arranged in the machining vessel in opposition to each other, the machining solution jetting means jets the machining solution delivered thereto, through the machining solution circulating system from the machining solution tank, towards the workpiece in the machining vessel in a predetermined order.

Abstract: In a wire cut electric discharge machining method, feeding units having wire electrode feeding mechanisms are provided for wire electrodes different in diameter, respectively. The feeding units are moved, one at a time, to a wire electrode feeding path by cylinders coupled detachably to thereto, respectively, whereby the wire electrodes different in diameter are automatically replaced with each other, and machining conditions are automatically selected according to the diameter of a wire electrode and a machining process which are to be used. Therefore, the workpiece can be machined with the wire electrode most suitable for the given machining configuration. Thus, the method is high in machining accuracy and in machining efficiency.

Abstract: In an electrical discharge machining apparatus, the average machining gap voltage is controlled to be a predetermined value even if a discharging operation is interrupted. This is accomplished by providing a bypass circuit or an inverse voltage providing circuit that responds to an interruption in the discharging operation. By controlling the average machining gap voltage, electrolytic corrosion and magnetization of the workpiece is minimized.

Abstract: The wire-cut electric discharge machine controls the mean voltage or mean current detected in the detection circuit in response to the variation of the feed rate of the workpiece. The electrostatic attractive force and discharge repulsive force act to the workpiece and make a balance. As a result, the arcuate shape distortion is canceled.

Abstract: An electrical discharge machining (EDM) apparatus having one or more dielectric tanks, each having one or more compartments, connected to an EDMing tank by pipes, defining input and output dielectric paths and having selectively placed therein pumps and control valves. The tanks are used for containing dielectric during roughing and finishing operations. Filters are used in the paths for removal of particles suspended in the dielectric. A filter loop with input and output paths containing a bidirectional filter can be used to filter and store finishing powders from a finishing dielectric and to regenerate the finishing dielectric by backwashing the filter with clean dielectric to replace the powder in the dielectric. Various combinations of inputs, discharge and filter paths may be used with various designs of dielectric tanks, having one or more compartments, in order to meet particular operational requirements.

Abstract: A wire-type electric discharge machining apparatus capable of attracting material from a workpiece to an integral electromagnet. An aperture is located proximate the electromagnet. When material is attracted by the electromagnet, the aperture will be obstructed. Attraction is confirmed by measuring the pressure in a chamber in communication with the aperture, such that a low pressure indicates obstruction, and thus attraction of the material to the electromagnet. If based on this measurement it appears that the material has not been attracted to the electromagnet, a further attempt is made at a different location of attraction.